Digital light processing three-dimensional printing system and method

ABSTRACT

A digital light processing (DLP) three-dimensional (3D) printing system includes a container containing a solidifiable material; a platform contacting a portion of the solidifiable material; a projector projecting an electromagnetic radiation on the solidifiable material to form a solidified layer; and an optical component between the projector and the platform; wherein the optical component is rotated to shift the electromagnetic radiation during the formation the solidified layer, thus forming a rounded edge and an enlarged area of the solidified layer. A digital light processing (DLP) three-dimensional (3D) printing method is also disclosed.

BACKGROUND 1. Field

The present disclosure is directed to 3D printing. More particularly,the present disclosure is directed to a digital light processing (DLP)three-dimensional (3D) printing system and method.

2. Background

3D (three-dimensional) printing is an effective technology foraccurately forming 3D objects for the purpose of prototyping andmanufacture. One commercially available 3D printing methodology isstereolithography. Stereolithography aims to create 3D objects based onthe successive formation of layers by a fluid-like medium adjacent topreviously formed layers of medium and the selective solidification ofthose layers according to cross-sectional data representing successiveslices of the desired three-dimensional object. Astereolithography-based system solidifying fluid medium may include aDLP (Digital Light Processing) projector. The DLP projector typicallyincludes a digital micromirror device (DMD). The DMD has a finite numberof pixels, therefore the electromagnetic radiation generated by the DMDis pixelated. The pixelated electromagnetic radiation is applied on thesolidifiable material. The pixelated electromagnetic radiation formspixels on the edge of each of the solidified layer, as illustrated inFIG. 1 and FIG. 2.

The product of DLP is formed from multiple solidified layers, thereforethe pixels on each layers are accumulated and transforms to thevolume-pixel. The volume-pixel, or voxel, is 3D structure formed bylayers of pixels on the solidified layer. The voxels on the edge of DLPproducts may result in rough or uneven surfaces on the product of DLP.

Referring to FIG. 3, a DLP system of 3D printing includes a platform, avat and a DLP projector. The DLP projector is located above the platformand the vat. The DLP projector projects UV (Ultra Violet) to aphotopolymer resin contained in the vat. The photopolymer resin will besolidified when being applied to UV. At least one part of the platformis positioned inside the vat and in contact with the photopolymer resin.The platform moves vertically after the UV is projected to thephotopolymer resin on the platform so the photopolymer on the platformcan be re-positioned. Then, the DLP projector will apply UV to a newlayer of non-solidified photopolymer resin. Multiple solidified layersof photopolymer resin form a 3D printing product. The 3D printingproduct can be removed from the platform after the 3D printing processis completed.

The DLP projector can be located under the platform, as illustrated inFIG. 4. The DLP projector projects UV to the photopolymer resin underthe platform, and the photopolymer resin under the platform issolidified. The platform moves upward after a solidified layer of thephotopolymer resin is formed to expose a new layer of non-solidifiedphotopolymer resin.

Nevertheless, the DMD of the DLP projector has limited pixels. Thesepixels of the DLP projector lead to pixelated edges of the solidifiedlayer. The DLP product is composed of many solidified layers, thereforethe pixels of each layer would be accumulated to form voxels.Low-resolution voxels are the cause of roughness on the surface of theDLP product.

To improve the roughness of conventional DLP products, the surface ofthe DLP product may be manually polished to remove rough edges and toform smooth appearances. However, the manual polishing process can becostly and time-consuming.

U.S. Pat. No. 7,790,093 disclosed a process improving the resolution ofthe DLP product, wherein a mirror is rotated along the Y-axis or theX-axis to shift the position of electromagnetic radiation projected onthe photopolymer resin, thus adjusting the area being applied to theelectromagnetic radiation. After that, the surface of the DLP product isneeded to be polished to remove rough edges formed from voxels. Furtherimprovements on forming the DLP products are desired.

SUMMARY

The present disclosure provides a DLP 3D printing system and method.

The present disclosure is directed to improvements on DLP technology in3D printing. More particularly, the present disclosure is directed to aDLP 3D printing system and a DLP 3D printing method to improve thequality of stereolithography products.

The present disclosure is further directed to a method for forming oneor more enlarged areas or rounded edges of the solidified layer in a DLP3D printing system.

The present disclosure is further directed to a DLP 3D printing systemwith at least one optical component. The optical component is a mirror,a lens, or a combination thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is illustrated by way of exemplary embodimentsand accompanying drawings.

FIG. 1 illustrates an arrangement of pixels of DMD in a conventional DLPprojector.

FIG. 2 illustrates another arrangement of pixels of DMD in aconventional DLP projector.

FIG. 3 illustrates a conventional DLP system, wherein the DLP projectoris located above the platform.

FIG. 4 illustrates a conventional DLP system, wherein the DLP projectoris located under the platform.

FIG. 5A illustrates a DLP system with the projector under the vataccording to an exemplary embodiment of the present disclosure.

FIG. 5B illustrates a DLP system with the projector above the vataccording to an exemplary embodiment of the present disclosure.

FIG. 6 illustrates an electromagnetic radiation projection of roundededges and enlarged area according to an exemplary embodiment of thepresent disclosure.

FIG. 7 illustrates a shifting route of a DLP projector according to anexemplary embodiment of the present disclosure.

FIG. 8 illustrates a circular shifting route and the diameter of thecircular shifting route of a DLP projector according to an exemplaryembodiment of the present disclosure.

FIG. 9A illustrates an original electromagnetic radiation projection of5 pixels according to an exemplary embodiment of the present disclosure.

FIG. 9B illustrates an improved electromagnetic radiation projectionhaving a circular shifting diameter of ½ pixel, and the improvedelectromagnetic radiation projection has enlarged areas when comparingwith FIG. 9A.

FIG. 9C illustrates an improved electromagnetic radiation projectionhaving a circular shifting diameter of 1 pixel, and the improvedelectromagnetic radiation projection has enlarged areas of theprojection when comparing with FIG. 9A.

FIG. 10A illustrates a DLP system with lens positioned above a projectorand under a vat according to an exemplary embodiment of the presentdisclosure.

FIG. 10B illustrates the process of forming an enlarged area of anelectromagnetic radiation projection according to FIG. 10A.

FIG. 10C illustrates a DLP system with lens positioned under a projectorand above a vat according to an exemplary embodiment of the presentdisclosure.

FIG. 11A illustrates the DLP system with mirror positioned in parallelwith a projector and under a vat according to an exemplary embodiment ofthe present disclosure.

FIG. 11B illustrates the process of forming an enlarged area of theelectromagnetic radiation projection according to FIG. 11A.

FIG. 11C illustrates the DLP system with mirror positioned in parallelwith a projector and above a vat according to an exemplary embodiment ofthe present disclosure.

FIG. 12 illustrates a DLP 3D printing method according to an exemplaryembodiment of the present disclosure.

DETAILED DESCRIPTION

The following description provides exemplary embodiments with specificdetails to one skilled in the art for a better understanding of thepresent disclosure. However, it should be understood that the presentdisclosure could be practiced even without these details. In someexemplary embodiments, to avoid unnecessarily obscuring the descriptionsof exemplary embodiments, well-known structures and functions are notillustrated or not described in detail. In the specification and claimsof the present disclosure, terms such as “including” and “comprising”should be comprehended as an inclusive meaning instead of an exclusiveor exhaustive meaning, i.e., it means “including but not limited to”unless specifically described otherwise in the context. In this detaileddescription section, singular or plural terms include both the pluraland singular meanings as well.

A digital light processing (DLP) three-dimensional (3D) printing systemis provided, the system comprising: a container containing asolidifiable material; a platform contacting a portion of thesolidifiable material; and a projector projecting an electromagneticradiation on the solidifiable material to form a solidified layer;wherein at least one of the platform and the projector are movable alonga predetermined path to shift the electromagnetic radiation during theformation the solidified layer, thus forming a rounded edge and anenlarged area of the solidified layer.

In an exemplary embodiment, the platform is above the projector, and theplatform moves upward after the solidified layer is formed in thecontainer.

In an exemplary embodiment, the platform is under the projector, and theplatform moves downward after the solidified layer is formed in thecontainer.

In an exemplary embodiment, the predetermined path is circular shiftingroute, and the circular shifting route is having a shifting diameter.

In an exemplary embodiment, the shifting diameter of the circularshifting route is less than or equal to 10 pixels.

A digital light processing (DLP) three-dimensional (3D) printing systemis also provided, the system comprising: a container containing asolidifiable material; a platform contacting a portion of thesolidifable material; a projector projecting an electromagneticradiation on the solidifiable material to form a solidified layer; andan optical component between the projector and the platform; wherein theoptical component is rotated to shift the electromagnetic radiationduring the formation of the solidified layer, thus forming a roundededge and an enlarged area of the solidified layer.

In an exemplary embodiment, the optical component is above the projectorif the projector is under the container.

In an exemplary embodiment, the optical component is under the projectorif the projector is above the container.

In an exemplary embodiment, the optical component is on a same planewith the projector.

In an exemplary embodiment, the optical component is a lens, a mirror ora combination thereof.

In an exemplary embodiment, the lens is a converging lens, a plane lens,a diverging lens or a combination thereof.

In an exemplary embodiment, the lens is rotated around a rotation axis,and the lens is tilted to refract the electromagnetic radiation from theprojector; and a tilt angle of the lens is an angle between a normalline of the refraction and the rotation axis.

In an exemplary embodiment, the rotation of the lens is activated by amotor coupled to the lens.

In an exemplary embodiment, the mirror is rotated around a rotationaxis, and the mirror is tilted; and a tilt angle of the mirror is anangle between the rotation axis and a normal line of a surface of themirror.

In an exemplary embodiment, the rotation of the mirror is activated by amotor coupled to the mirror.

In an exemplary embodiment, the combination of the lens and the mirrorcomprises at least one mirror and at least one lens; the mirror reflectsthe electromagnetic radiation and the electromagnetic radiationreflected by the mirror is then refracted by the lens; the mirror or thelens is rotated around a rotation axis, and the mirror or the lens istilted from the rotation axis.

In an exemplary embodiment, the combination of the lens and the mirrorcomprises at least one mirror and at least one lens; the lens refractsthe electromagnetic radiation, and the electromagnetic radiationrefracted by the lens is then reflected by the mirror; the mirror or thelens is rotated around a rotation axis, and the mirror or the lens istilted from the rotation axis.

A digital light processing (DLP) three-dimensional (3D) printing methodis also provided, the method comprising: projecting an electromagneticradiation from the projector on a solidifiable material contained in acontainer, wherein the solidifiable material is supported by a platform;and modifying the electromagnetic radiation to form a rounded edge ofthe solidified layer or an enlarged area of the solidified layer whenforming a solidified layer from the solidifiable material through theelectromagnetic radiation.

In an exemplary embodiment, modifying the electromagnetic radiation toform the rounded edge or the enlarged area is accomplished by tilting orrotating of a lens, a mirror or combination thereof, which is positionedbetween the projector and the platform.

In an exemplary embodiment, modifying the electromagnetic radiation toform the rounded edge or the enlarged area is accomplished by movementof the projector along a predetermined path.

In an exemplary embodiment, modifying the electromagnetic radiation toform the rounded edge and the enlarged area is accomplished by movementof the platform along a predetermined path.

In an exemplary embodiment, the predetermined path is on the X-Y plane.

In an exemplary embodiment, the predetermined path is a circularshifting route, and the predetermined path is having a shiftingdiameter.

In an exemplary embodiment, a shifting diameter of the circular shiftingroute is less than or equal to 10 pixels.

The term “X axis” refers to a direction runs horizontally in FIG. 1 toFIG. 4, and FIG. 6 to FIG. 11C in exemplary embodiments of the presentdisclosure. The term “Y axis” refers to a direction runs vertically inFIG. 1, FIG. 2, FIG. 6, FIG. 7, FIG. 8, and FIG. 9A to FIG. 9C inexemplary embodiments of the present disclosure. “Y axis” also refers toa direction runs into or out of the page plane in FIG. 3, FIG. 4, FIG.10A to FIG. 10C, and FIG. 11A to FIG. 11C in exemplary embodiments ofthe present disclosure. The term “Z axis” refers to a direction runsvertically in FIG. 3, FIG. 4, FIG. 10A to FIG. 10C, and FIG. 11A to FIG.11C in exemplary embodiments of the present disclosure. The “X-Y plane”refers to a plane formed by X axis and Y axis, wherein FIG. 1, FIG. 2,FIG. 6 to FIG. 8, and FIG. 9A to FIG. 9C are illustrations of exemplaryembodiments on the X-Y plane, in accordance with the present disclosure.The “X-Z plane” refers to a plane formed by X axis and Z axis, whereinFIG. 3, FIG. 4, FIG. 10A to FIG. 10C, and FIG. 11A to FIG. 11C areillustrations of exemplary embodiments on the X-Z plane, in accordancewith the present disclosure. The X axis, the Y axis and the Z axis inFIG. 5A and FIG. 5B are defined in the figures, respectively.

Referring to FIG. 5A, 5B and FIG. 6, a DLP 3D printing system 100, a DLP3D printing system 100′ and a DLP 3D printing method in accordance withexemplary embodiments of the present disclosure are provided. As shownin FIG. 5A, the system 100 includes a projector 1 which generates anelectromagnetic radiation 2. That is, the projector 1 is a source of theelectromagnetic radiation 2. The system 100 may also include a container3 to contain a solidifiable material, and the solidifiable materialforms a solidified layer when exposed to the electromagnetic radiation 2generated by the projector 1. The electromagnetic radiation 2 forms anelectromagnetic radiation projection 21 on the surface of thesolidifiable material. The container 3, for example, is a vat 3. Thesystem 100 may further include a platform 4. At least one part of theplatform 4 is inside the vat 3 and in contact with a portion of thesolidifiable material. The portion of the solidifiable material becomesa solidified layer after being applied to the electromagnetic radiation2. The platform 4 moves upward after a solidified layer is formed, andthe newly formed solidified layer is carried by the platform 4. Afterthe movement of the platform 4, another portion of the solidifiablematerial under the newly formed solidified layer will be ready toreceive the electromagnetic radiation 2. Referring to FIG. 5A, theprojector 1 is configured to be under the vat 3, the platform 4 would beabove the vat 3, and the platform 4 moves upward after the solidifiedlayer is formed.

Referring to FIG. 5B, a DLP 3D printing system 100′ in accordance withexemplary embodiments of the present disclosure is provided. Theprojector 1′ is configured to be above the vat 3′. At least one part ofthe platform 4′ is inside the vat 3′ and in contact with a portion ofthe solidifiable material. The portion of the solidifiable materialbecomes a solidified layer after being applied to the electromagneticradiation 2′.

The platform 4′ moves downward after the solidified layer is formed, andthe newly formed solidified layer is carried by the platform 4′. Afterthe movement of the platform 4′, another portion of the solidifiablematerial above the newly formed solidified layer will be ready toreceive the electromagnetic radiation 2′.

The projector 1 or platform 4 may be movable along a predetermined pathto shift the electromagnetic radiation 2 during the formation of thesolidified layer, thus forming an electromagnetic radiation projection22 with rounded edges 5 or enlarged areas 6, as shown in FIG. 6. Thepredetermined path may be on the X-Y plane. In an exemplary embodiment,an actuator (not shown) may be coupled to the projector 1 or theplatform 4 to facilitate the movement of the projector 1 or the platform4. The actuator can be a motor mechanism, and the motor mechanism ispredetermined in the DLP 3D printing system. The solidifiable materialwill form a solidified layer by the shape of electromagnetic radiationprojection 22 in FIG. 6.

When the projector 1′ is configured to be above the vat 3′, the platform4′ moves downward after the solidified layer is formed in the vat 3′.When the projector 1 is configured to be under the vat 3, the platform 4would be above the vat 3, and the platform 4 moves upward after thesolidified layer is formed in the vat 3. The platform (4, 4′) may beshifted in a plane relative to the projector (1, 1′) to formelectromagnetic radiation projections 22 of rounded edges and enlargedarea. The platform (4, 4′) may be shifted in the X-Y plane.

The DLP 3D printing system 100 may generate multiple electromagneticradiation projections of rounded edges and enlarged areas. Asolidification process is the formation of a solidified layer when beingapplied to an electromagnetic radiation projection 21. In an exemplaryembodiment of the present disclosure, the solidifiable material can be aphotopolymer resin. A solidified layer is formed when being applied tothe electromagnetic radiation projection 21. The shape of the solidifiedlayer corresponds to the shape of the electromagnetic radiationprojection 21.

The projector 1 includes a DMD. The DMD is the source of electromagneticradiation 2 and generates at least one wavelength of electromagneticradiation 2. The wavelength of the electromagnetic radiation 2 isdependent on the solidifiable material used in the DLP 3D printingsystem 100. The electromagnetic radiation 2 has a range of wavelength ofabout 350 nm to 550 nm. Preferably, the wavelength of theelectromagnetic radiation 2 is about 405 nm. The electromagneticradiation 2 can be UV. One or more original images are inputted into theprojector 1 to be processed into an electromagnetic radiationprojection. At least one of the platform 4 and the projector 1 ismovable along a predetermined path, and the electromagnetic radiation isprojected to the solidifiable material, thus forming rounded edges 5 ofthe solidified layer and enlarged areas 6 of the solidified layer. Asillustrated in FIG. 7, the projector 1 may be shifted relative to thevat to form electromagnetic radiation projections 21 of rounded edgesand enlarged area. As illustrated in FIG. 8, the shifting route 7, i.e.,the predetermined path, may be a circular shifting route. The circularshifting route 7 moves around a center 8, and the circular shiftingroute 7 has a diameter 9 relative to the center 8. The circular shiftingroute 7 may be on the X-Y plane. As illustrated in FIG. 9A, there are 5pixels in the original electromagnetic radiation projection 21. However,as illustrated in FIG. 9B, the area of the electromagnetic radiationprojection 22 a is enlarged comparing to the original image. Thecircular shifting diameter is positively correlated to the enlarged areaof the electromagnetic radiation projection 22 a; and the larger thecircular shifting diameter, the larger the enlarged area. The circularshifting diameter is less than 10 pixels. The circular shifting diametermay include, but not be limited to ½ pixel as shown as FIG. 9B, or 1pixel as shown as FIG. 9C. The circular shifting diameter can be aninteger multiple of one pixel, such as 1, 2, 3, 4, 5, 6, 7 or 8 pixels.The circular shifting diameter can also be a non-integer multiple of onepixel, such as 0.5, 1.11, 2.11 or 3.33 pixels.

The vat 3 is comprised of one or more transparent materials. Theelectromagnetic radiation 2 from the projector 1 is able to pass throughthe transparent material of the vat 3 and reach the solidifiablematerial contained in the vat.

In an exemplary embodiment, the system may include an optical componentbetween the source of electromagnetic radiation 1 and the platform 4.The optical component can be a lens 10 a, a mirror 10 b or a lens/mirrorcombination. The optical component may be tilted and rotated to directthe electromagnetic radiation 2 to form a rounded contour on the edge ofthe projection.

The optical component is positioned between the source of theelectromagnetic radiation 2 and the vat 3. The arrangement of theoptical component in the DLP 3D printing system is dependent on theposition of the projector 1 and the vat 3. The optical component can beabove the projector 1 if the projector 1 is under the vat 3. The opticalcomponent 10 can also be under the projector 1 if the projector 1 isabove the vat 3. The optical component 10 can also be located on thesame plane with the projector 1. The optical component may change theroute of the electromagnetic radiation 2 from the projector 1, and maychange the shape of the electromagnetic radiation projection 21 on thesolidifiable material. The optical component can be any one of a lens, amirror or a lens/mirror combination.

A DLP 3D printing system 200 in accordance with exemplary embodiments ofthe present disclosure is provided. The optical component is the lens 10a as shown in FIG. 10A. The lens 10 a can be a converging lens, a planelens, a diverging lens or a combination thereof. Referring to FIG. 10A,the projector 1 is under the vat 3, and the lens 10 a is positionedabove the projector 1 and located between the projector 1 and the vat 3.Referring to FIG. 10A, the lens 10 a is rotated around a rotation axis11, and the lens 10 a is tilted to refract the electromagnetic radiation2 from the projector 1. The electromagnetic radiation 2 is refracted bythe lens 10 a, and the tilt angle 12 of the lens 10 a is the anglebetween the normal line 13 of the surface of the lens 10 a and therotation axis 11. The tilted rotating lens 10 a may enlarge theelectromagnetic radiation projection 22 as shown as FIG. 10B. The tiltangle 12 of the lens 10 a is positively correlated to the enlarged area14 of the electromagnetic radiation. The tilt angle 12 may bepredetermined or programmed in the DLP 3D printing system 200 of thepresent disclosure, in accordance with the size of the enlarged area.The tilt angle 12 can be affected by material and optical properties ofthe lens 10 a. When setting the tilt angle 12, the refractive index(RI), the thickness or the focus of the lens 10 a may be determinants ofthe tilt angle 12. The tilt angle 12 can be 1° to 45°. Preferably, thetile angle 12 can be 5°.

Referring to FIG. 10C, a DLP 3D printing system 200′ in accordance withexemplary embodiments of the present disclosure is provided. Theprojector 1′ is above the vat 3′, the lens 10 a′ is positioned under theprojector 1′ and located between the projector 1′ and the vat 3′ in theDLP 3D printing system 100′ in an exemplary embodiment. The lens 10 a′is tilted to refract the electromagnetic radiation 2′ from the projector1′.

A DLP 3D printing system 300 in accordance with exemplary embodiments ofthe present disclosure is provided. The optical component 10 is themirror 10 b as shown as FIG. 11A. The projector 1 is under the vat 3,the mirror 10 b can be positioned in parallel with the projector 1 andunder the vat 3. The mirror 10 b may reflect the electromagneticradiation 2 generated by the DMD in the projector 1. The mirror 10 b isrotated around a rotation axis 11. The rotation is activated by a motor15 coupled to the mirror 10 b. The mirror 10 b is tilted, and the tiltangle 12 of the mirror 10 b is the angle between the rotation axis and anormal line 13 of the surface of the mirror 10 b. When comparing withthe original image, the electromagnetic radiation projection 22 isenlarged because of the tilted rotational mirror as shown as FIG. 11B.The tilt angle 12 of the mirror 10 b is positively correlated to theenlarged area 14 of the projection. The tilt angle 12 may bepredetermined or programmed in the DLP 3D printing system 300 of thepresent disclosure, in accordance with the size of the enlarged area 14.The tilt angle 12 can be affected by various determinant in the DLP 3Dprinting system 300 illustrated in FIG. 11A and FIG. 11B. The distancebetween center of the mirror 10 b and the image focus plane, the imagerotation shift radius and the focus of the mirror 10 b can bedeterminants when setting the tilt angle 12. Preferably, the tilt angle12 is less than 1°.

A DLP 3D printing system 300′ in accordance with exemplary embodimentsof the present disclosure is provided. Referring to FIG. 11C, theprojector 1′ is above the vat 3′, the mirror 10 b′ can be positioned inparallel with the projector 1′ and above the vat 3′ in the DLP 3Dprinting system 300′ in an exemplary embodiment. The mirror 10 b′ mayreflect the electromagnetic radiation 2′ generated by the DMD in theprojector 1′.

In an exemplary embodiment, the optical component is a mirror/lenscombination. The mirror/lens combination includes at least one mirrorand at least one lens. The mirror/lens combination is positioned betweenthe projector and the vat. The mirror reflects the electromagneticradiation generated by the DMD in the projector, and the electromagneticradiation reflected by the mirror is refracted by the lens. The lens canalso be positioned to refract the electromagnetic radiation generated bythe DMD in the projector, and the electromagnetic radiation refracted bythe lens is then reflected by the mirror. The mirror or the lens can berotated, and the mirror or the lens can be tilted from the rotationaxis. Enlarged areas may be present in the electromagnetic radiationprojection, and the enlarged areas of the electromagnetic radiationprojection are positively correlated to the tilt angle of the mirror orthe lens.

In an exemplary embodiment, the DLP system may include at least onelens, a projector, a platform and a vat. One or more lenses are locatedbetween the projector and the platform. The lens can be a converginglens, a plane lens, a diverging lens or a combination thereof. If theprojector is under the vat, the lens is positioned above the projectorand between the projector and the vat. If the projector is above thevat, the lens is positioned under the projector and between theprojector and the vat. The electromagnetic radiation generated by theDMD in the projector is refracted by the lens. The refractedelectromagnetic radiation forms at least one electromagnetic radiationprojection on the solidifiable material in the vat. The lens is rotatedaround a rotation axis, and the lens is tilted. The rotation of the lensis activated by a motor coupled to the lens. The tilt angle of the lensis the angle between the normal line of the refraction and the rotationaxis. The tilted rotating lens may enlarge the electromagnetic radiationprojection. The tilt angle of the lens is positively correlated to theenlarged area of the projection.

In an exemplary embodiment, the DLP system may include at least onemirror, a projector, a platform and a vat. One or more mirrors arelocated in parallel with the electromagnetic radiation source. Themirror reflects the electromagnetic radiation generated by the DMD inthe projector. The mirror is rotated around a rotation axis. Therotation is activated by a motor coupled to the mirror. The mirror istilted, and the tilt angle of the mirror is the angle between therotation axis and a normal line of the surface of the mirror. The tiltedmirror may enlarge the electromagnetic radiation projection. The tiltangle of the mirror is positively correlated to the enlarged area of theprojection.

In an exemplary embodiment, the DLP system may include at least onemirror, at least one lens, a projector, a platform and a vat. Theelectromagnetic radiation generated by the DMD in the projector can bereflected by the mirror and then refracted by the lens to reach the vat.The electromagnetic radiation generated by the DMD in the projector canalso be refracted by the lens and then reflected by the mirror to reachthe vat. The lens or the mirror can be rotated or tilted to form anelectromagnetic radiation projection of rounded edges and enlarged areasrelative to the original image. The rotation mechanism is activated by amotor coupled to the lens or the mirror.

In an exemplary embodiment, the DLP system may include a movableprojector, a platform and a vat. The projector is movable relative tothe platform. The projector is shifted during one solidification processto form electromagnetic radiation projections of rounded edges andenlarged area. The projector can be shifted in a circular manner. Thecircular shifting moves around a center, and the circular shifting has adiameter relative to the center. At least one circular shifting may becompleted in a single solidification process. To ensure the size anddetail appearances of the DLP product are not altered dramatically, thecircular shifting diameter is less than or equal to 10 pixels.

In an exemplary embodiment, the present disclosure is further directedto an improved stereolithography process, in particular, a DLP 3Dprinting method. Referring to FIG. 12, the method includes:

S1: inputting an image for stereolitography: the user may input a 3Ddesign of an object to the DLP 3D printing system. The 3D design can besliced into multiple layers of images manually or automatically. Thelayers of images may be modified. The projector receives original ormodified image of each layer to form one or more electromagneticradiation projections.

S2: projecting an electromagnetic radiation from the projector to thevat: the electromagnetic radiation is shifted, refracted or reflected toform a rounded contour or enlarged areas relative to the original imageon the solidifiable material in the vat. The shifting, refraction orreflection of the electromagnetic radiation may be contributed to themovement of any one or more of the following components in the DLPsystem, and the movement, tilt and rotation of the components areprogrammed so that the electromagnetic radiation projections aremodifications of the original image.

The tilt angle of the lens, the mirror or the lens/mirror combinationcorresponds to the enlarged area of the electromagnetic radiationprojection.

The shifting of the projector: the projector can be shifted relative tothe platform to form the shape of the electromagnetic radiationprojection. The shifting route of the projector can be a circular route.The circular shifting route may surround a center. The circular shiftingroute may have a diameter. Larger circular shifting diameter representslarger enlarged areas.

The shifting of the platform: the platform can be shifted relative tothe projector to form the shape of the electromagnetic radiationprojection.

S3, forming a solidified layer: the solidified layer is formed from thesolidifiable material in the vat. The solidified layer has a shapecorresponds to the electromagnetic radiation projection. When comparingwith the original image, the shape of the solidified layer has a roundededge and enlarged areas.

The DLP product in accordance with exemplary embodiments of the presentdisclosure would have rounded edges. The DLP product would not need tobe polished after the product leaves the DLP system, therefore greatlyreduces time and cost needed for polishing.

It is to be further understood that even though numerous characteristicsand advantages of the present exemplary embodiments have been set forthin the foregoing description, together with details of the structuresand functions of the exemplary embodiments, the disclosure isillustrative only, and changes may be made in details, especially inmatters of shape, size, and arrangement of parts within the principlesof the disclosure to the full extent indicated by the broad generalmeaning of the terms in which the appended claims are expressed.

What is claimed is:
 1. A digital light processing (DLP)three-dimensional (3D) printing system, comprising: a containercontaining a solidifiable material; a platform contacting a portion ofthe solidifiable material; and a projector projecting an electromagneticradiation on the portion of the solidifiable material contacting theplatform to form a solidified layer; wherein at least one of theplatform and the projector are movable along a predetermined path toshift the electromagnetic radiation during the formation the solidifiedlayer, thereby forming a rounded edge and an enlarged area of thesolidified layer.
 2. The system of claim 1, wherein the platform isabove the projector, the platform moves upward after the solidifiedlayer is formed in the container.
 3. The system of claim 1, wherein theplatform is under the projector, the platform moves downward after thesolidified layer is formed in the container.
 4. The system of claim 1,wherein the predetermined path is on the X-Y plane.
 5. The system ofclaim 1, wherein the predetermined path is a circular shifting route,and the circular shifting route is having a shifting diameter.
 6. Thesystem of claim 5, wherein the shifting diameter of the circularshifting route is less than or equal to 10 pixels.
 7. A digital lightprocessing (DLP) three-dimensional (3D) printing system, comprising: acontainer containing a solidifiable material; a platform contacting aportion of the solidifiable material; a projector projecting anelectromagnetic radiation on the portion of the solidifiable materialcontacting the platform to form a solidified layer; and an opticalcomponent between the projector and the platform; wherein the opticalcomponent is rotated to shift the electromagnetic radiation during theformation of the solidified layer, thereby forming a rounded edge and anenlarged area of the solidified layer.
 8. The system of claim 7, whereinthe optical component is above the projector if the projector is underthe container.
 9. The system of claim 7, wherein the optical componentis under the projector if the projector is above the container.
 10. Thesystem of claim 7, wherein the optical component is on a same plane withthe projector.
 11. The system of claim 7, wherein the optical componentis a lens, a mirror or a combination thereof.
 12. The system of claim11, wherein the lens is a converging lens, a plane lens, a diverginglens or a combination thereof.
 13. The system of claim 11, wherein thelens is rotated around a rotation axis, and the lens is tilted torefract the electromagnetic radiation from the projector; and a tiltangle of the lens is an angle between a normal line of the refractionand the rotation axis.
 14. The system of claim 13, wherein the rotationof the lens is activated by a motor coupled to the lens.
 15. The systemof claim 11, wherein the mirror is rotated around a rotation axis, andthe mirror is tilted; and a tilt angle of the mirror is an angle betweenthe rotation axis and a normal line of a surface of the mirror.
 16. Thesystem of claim 15, wherein the rotation of the mirror is activated by amotor coupled to the mirror.
 17. The system of claim 11, wherein thecombination of the lens and the mirror comprises at least one mirror andat least one lens; the mirror reflects the electromagnetic radiation andthe electromagnetic radiation reflected by the mirror is refracted bythe lens; the mirror or the lens is rotated around a rotation axis, andthe mirror or the lens is tilted from the rotation axis.
 18. The systemof claim 11, wherein the combination of the lens and the mirrorcomprises at least one mirror and at least one lens; the lens refractsthe electromagnetic radiation, and the electromagnetic radiationrefracted by the lens is reflected by the mirror; the mirror or the lensis rotated around a rotation axis, and the mirror or the lens is tiltedfrom the rotation axis.
 19. A digital light processing (DLP)three-dimensional (3D) printing method, comprising: projecting anelectromagnetic radiation from a projector on a solidifiable materialcontained in a container, the platform contacting a portion of thesolidifiable material; and modifying the electromagnetic radiation toform a rounded edge of the solidified layer and an enlarged area of thesolidified layer during the formation of a solidified layer from thesolidifiable material through the electromagnetic radiation.
 20. Themethod of claim 19, wherein modifying the electromagnetic radiation toform the rounded edge or the enlarged area by tilting or rotating of anoptical component, the optical component is positioned between theprojector and the platform.
 21. The method of claim 20, wherein theoptical component is a lens, a mirror or combination thereof.
 22. Themethod of claim 19, wherein modifying the electromagnetic radiation toform the rounded edge or the enlarged area by movement of the projectoror the platform along a predetermined path.
 23. The method of claim 22,wherein the predetermined path is a circular shifting route, and thepredetermined path is having a shifting diameter.
 24. The method ofclaim 23, wherein the shifting diameter of the circular shifting routeis less than or equal to 10 pixels.